Nallamothu Brahmajee K, Bradley Elizabeth H, Krumholz Harlan M
Health Services Research and Development Center of Excellence, Ann Arbor Veterans Affairs Medical Center, and the Department of Internal Medicine, Division of Cardiovascular Disease, University of Michigan Medical School, Ann Arbor, USA.
N Engl J Med. 2007 Oct 18;357(16):1631-8. doi: 10.1056/NEJMra065985.